SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2de94f357c145124de8540aa949ffc6543a1ded2927dc4d668d87ade42f8c38' 
  AND token = 'IOXvFfkg9UmH3VgbUg19gM1JM2GTSJAnODLGPPZQmcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}